Adaptive beam-forming with interference suppression and multi-user detection in satellite systems with terrestrial reuse of frequencies
Dunmin Zheng, P.D. Karabinis · 2006
Adaptive space-time signal processing comprising interference suppression and multi-user detection in a CDMA Mobile Satellite System (MSS) environment is presented. Optimum beam-forming, based on a Minimum Mean-Squared Error (MMSE) performance index, is used to maximize the signal-to-noise plus interference ratio of MSS links in an environment of significant terrestrial reuse of the satellite service link frequencies by Ancillary Terrestrial Components (ATCs). The technique substantially mitigates both ATC-induced co- channel interference and Multiple-Access Interference (MAI). At the satellite gateway, a pilot-based MMSE algorithm is used to adaptively form an optimum return-channel beam for each user by processing the raw antenna feed element signals provided to the satellite gateway by a satellite return feeder link. Following beam-forming, pilot signals are used to estimate the multi-user channels. The proposed Sequential ATC and MAI Interference Canceller (SAMIC) algorithm takes advantage of a priori known pilot signal information and invokes preliminary decisions to sequentially perform interference suppression followed by multi- user detection. The performance of the SAMIC algorithm is illustrated by simulation of a multi-beam geo-stationary satellite system containing a wide deployment of ATC over 50 major markets across the Continental United States (CONUS).